Analysis of phenotypic changes in high temperature and low pH extreme conditions of Alicyclobacillus sendaiensis PA2 related with the cell wall and sporulation genes.

The A. sendaiensis PA2 is a polyextremophile bacterium. In this study, we analyze the A. sendaiensis PA2 genome. The genome was assembled and annotated. The A. sendaiensis PA2 genome structure consists of a 2,956,928 bp long chromosome and 62.77% of G + C content. 3056 CDSs were predicted, and 2921 genes were assigned to a putative function. The ANIm and ANIb value resulted in 97.17% and 96.65%, the DDH value was 75.5%, and the value of TETRA (Z-score) was 0.98. Comparative genomic analyses indicated that three systems are enriched in A. sendaiensis PA2. This strain has phenotypic changes in cell wall during batch culture at 65 °C, pH 5.0 and without carbon and nitrogen source. The presence of unique genes of cell wall and sporulation subsystem could be related to the adaptation of A. sendaiensis PA2 to hostile conditions.

Toxicological and Sedative Effects of Chipilin (Crotalaria longirostrata) Leaf Extracts Obtained by Maceration and Supercritical Fluid Extraction.

Chipilin (Crotalaria longirostrata) is consumed as a vegetable in the preparation of traditional dishes. As a folk medicine, Chipilin extracts are used as a hypnotic and sedative agent; however, there are few reports that support these uses. This study aimed to characterize the compounds present in Chipilin leaf extracts and to investigate their sedative effect using zebrafish as an in vivo model. Extracts were obtained by maceration with water (H2O), ethanol (EtOH), and EtOH-H2O, while oleoresin was obtained by supercritical fluid extraction (SFE). Total phenolic and flavonoid contents were quantified by colorimetric methods. Phytochemical constituents were identified by gas chromatography-mass spectrometry (GC-MS) analysis. The chronic and acute toxicities of Chipilin extracts were tested in zebrafish embryos and larvae, respectively. Chipilin sedative effect was tested by the larvae response to dark-light-dark transitions. EtOH-H2O extracts had the highest value of total phenolics (5345 ± 5.1 µg GAE/g), followed by water and oleoresin (1815 ± 5.1 and 394 ± 5.1 µg GAE/g, respectively). In water extracts were identified the alkaloid trachelanthamidine, 1,2ß-epoxy- and the alkyl ketone 7,9-di-tert-butyl-1-oxaspiro(4,5)deca-6,9-diene-2,8-dione, while oleamide, α-monostearin, and erucamide were detected in all samples except in water extracts. Oleoresin extract had the lowest embryotoxicity (LC50 = 4.99 µg/mL) and the highest sedative effects. SFE is a green alternative to obtain Chipilin extracts rich in erucamide, an endocannabinoid analogue, which plays an important role in the development of the central nervous system and in modulating neurotransmitter release.

Analyzing the gut microbiota and microbial-associated metabolites of tomato-based sauces.

Red Cooked Sauce (RCS) and Red Raw Sauce (RRS) are a mixture of natural crops that have a promising content of bioactive compounds (BC). The aim was to determine the effect of the indigestible fraction (IF) during the colonic fermentation in RCS and RRS by studying the two-way relationship between gut microbiota composition and microbial metabolites produced from BC fermented in the TNO in vitro dynamic model of the human colon (TIM-2). Total BC in undigested and predigested RRS, 957 and 715 mg/100 g DW, respectively, was significantly higher (p < 0.05) than in the RCS, 571 and 406 mg/100 g DW, respectively. Catenibacterium and Holdemanella increased during RCS fermentation, while 13 genera showed a clear positive correlation with most microbial phenolic metabolites. Our findings suggest that the mechanisms, pathways, and enzymes involved in producing microbial metabolites exhibited uniqueness among bacterial taxa, even within shared genus/family classifications.

Effect of plant growth-promoting bacteria on the growth and fructan production of Agave americana L

ABSTRACT The effect of plant growth-promoting bacteria inoculation on plant growth and the sugar content in Agave americana was assessed. The bacterial strains ACO-34A, ACO-40, and ACO-140, isolated from the A. americana rhizosphere, were selected for this study to evaluate their phenotypic and genotypic characteristics. The three bacterial strains were evaluated via plant inoculation assays, and Azospirillum brasilense Cd served as a control strain. Phylogenetic analysis based on the 16S rRNA gene showed that strains ACO-34A, ACO-40 and ACO-140 were Rhizobium daejeonense, Acinetobacter calcoaceticus and Pseudomonas mosselii, respectively. All of the strains were able to synthesize indole-3-acetic acid (IAA), solubilize phosphate, and had nitrogenase activity. Inoculation using the plant growth-promoting bacteria strains had a significant effect (p < 0.05) on plant growth and the sugar content of A. americana, showing that these native plant growth-promoting bacteria are a practical, simple, and efficient alternative to promote the growth of agave plants with proper biological characteristics for agroindustrial and biotechnological use and to increase the sugar content in this agave species.

Symbiotic potential and survival of native rhizobia kept on different carriers

Native rhizobia are ideal for use as commercial legume inoculants. The characteristics of the carrier used to store the inoculants are important for the survival and symbiotic potential of the rhizobia. The objective of this study was to investigate the effects of peat (PEAT), perlite sugarcane bagasse (PSB), carboxymethyl cellulose plus starch (CMCS), and yeast extract mannitol supplemented with mannitol (YEMM) on the survival, nodulation potential and N₂ fixation capacity of the native strains Sinorhizobium mexicanum ITTG R7^T and Rhizobium calliandrae LBP2-1^T and of the reference strain Rhizobium etli CFN42^T. A factorial design (4 × 3) with four repetitions was used to determine the symbiotic potential of the rhizobial strains. The survival of the strains was higher for PEAT (46% for strain LBP2-1^T, 167% for strain CFN42^T and 219% for strain ITTG R7^T) than for the other carriers after 240 days, except for CFN42^T kept on CMCS (225%). All the strains kept on the different carriers effectively nodulated common bean, with the lowest number of nodules found (5 nodules) when CFN42^T was kept on CMCS and with the highest number of nodules found (28 nodules) when ITTG R7^T was kept on PSB. The nitrogenase activity was the highest for ITTG R7^T kept on PEAT (4911 μmol C₂H₄ per fresh weight nodule h⁻¹); however, no activity was found when the strains were kept on YEMM. Thus, the survival and symbiotic potential of the rhizobia depended on the carrier used to store them.